Compressor for cam follower spring

ABSTRACT

The present invention is directed to a tool for use on diesel engine cylinder heads having a plurality of recessed cam follower springs secured under compression in recesses within the cylinder head by follower spring seat retainers. The tool of the present invention can be removably secured to the cylinder head and will serve to compress the cam follower spring to permit removal of the follower spring seat retainer and subsequent removal of the cam follower assembly.

United States Patent Fagen [54] COMPRESSOR FOR CAM FOLLOWER SPRING [72] Inventor: John Fagen, 2318 W. Fourth Avenue,

Kennewick, Wash. 99336 [22] Filed: Feb. 19, 1971 [21] Appl. No.: 116,921

[52] US. Cl ..29/217 [51] Int. 1323p 19/08 [58] Field of Search ..29/215, 216, 217, 227, 220

[56] References Cited UNITED STATES PATENTS 1,849,538 3/1932 Bemitz ..29/216 X 2,173,398 9/1939 Michener ..29/220 [451 July 18,1972

Binkley ..29/217 Hewett ..29/217 Primary Examiner-Robert C. Riordon Assistant Examiner-J. C. Peters Attorney-Kraffi & Wells l 5 ABSTRACT The present invention is directed to a tool for use on diesel engine cylinder heads having a plurality of recessed cam follower springs secured under compression in recesses within the cylinder head by follower spring seat retainers. The tool of the present invention can be removably secured to the cylinder head and will serve to compress the cam follower spring to permit removal of the follower spring seat retainer and subsequent removal of the cam follower assembly.

5 Chain, 3 [having Figures Patented July 18, 1972 3,676,913

2 Sheets-Sheet l INVENTOR JOHN FAGEN ATTORNEYS Patented July 18, 1972 2 Sheets-Sheet 2 JOHN 251322 ATTORN EYS COMPRESSOR FOR CAM FOLLOWER SPRING BACKGROUND OF THE INVENTION A popular type of diesel engine having particularly wide application as a truckpower plant is known as the Detroit Diesel Engine. This engine is manufactured under several names and in several models, but each of these models have in common a particular design feature which has caused a problem in the maintenance, overhaul and repair thereof. Each cylinder of the Detroit Diesel Engine is provided with two exhaust valves and a fuel injector. These exhaust valves and the fuel injector are actuated by rocker arms which are in turn each actuated by a corresponding cam follower assembly. The respective cam follower assemblies are actuated by lobes on a common cam shaft.

In the repair, maintenance and overhaul of these engines, it is necessary to remove these cam follower assemblies. Each cam follower assembly consists of a cam follower, a cam follower spring and a cam follower push rod, together with associated hardware. Each cam follower assembly is located in an appropriate cylindrical hole in the head of the engine. When in place in the head of the engine, the cam follower spring is compressed and is maintained in position by a cam follower spring seat retainer which fits into an appropriate groove in the upper portion of the cylindrical hole in the head of the engine.

To remove the cam follower assembly for inspection and part replacement and to inspect the condition of the cam lobes, it is necessary to compress the cam follower spring in order that the cam follower spring seat retainer, commonly known as the keeper ring can be removed from its groove. Conversely, upon reassembly, it is necessary to compress the cam follower spring before the keeper ring can be replaced in its groove. Because the cam follower spring when compressed is positioned completely within the cylindrical hole in the engine head, the removal and replacement of the keeper ring has been a cumbersome and awkward task.

SUMMARY OF THE INVENTION ln accordance with the present invention, a new novel and useful tool is provided which can be readily and quickly attached to the cylinder head of a Detroit Diesel Engine and which can be used to easily compress the cam follower springs on such engines to enable the mechanic to quickly install or remove the keeper ring. This tool is secured to the head of the engine using the threaded holes normally securing the rocker arm bolts in position. Because the rocker arm bolts must be removed prior to removal of the cam follower spring, these tapped holes are readily available for such use. The tool is so designed that upon installation on the engine head at a position corresponding to a particular cylinder, it can be employed to compress any one of the three cam follower springs associated with that cylinder without removal and reattachment to the cylinder head. Once in place on the cylinder head the tool is so designed that the actuating mechanism is shiftable laterally along a base bar and is readily positionable so that any selected cam follower spring associated with a particular cylinder can be compressed.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, perspective view of a portion of a cylinder head of a diesel engine showing the cam follower spring compressor of the present invention mounted thereon. For purposes of illustration certain parts have been broken away;

FIG. 2 is a side elevation view of the cam follower spring compressor of the present invention mounted on a cylinder head of a diesel engine which is shown in fragmentary section to better illustrate the operation of the device of the present invention; and

FIG. 3 is an exploded view of the cam follower spring compressor of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, there is shown a preferred embodiment of the cam follower spring compressor of the present invention. As illustrated, the device consists of an elongated central or base bar 10, preferably of square crosssection, which is secured at its ends by connecting means 11 to securing bolts 12. The securing bolts 12 are designed to secure the device to the rocker arm bolt holes in the cylinder head of a diesel engine. Pivotally and slidably mounted on the base bar 10 between the securing bolts 12 is a spring compressor assembly 13. The spring compressor assembly 13 includes a spring compressor unit 14 having a tubular lower portion 15 which is designed to fit over a cam follower push rod. The terminal surface 16 of the spring compressor unit is designed to bear upon a follower upper spring seat as will be explained in detail hereinbelow. The spring compressor unit 14 is connected by pivot means 17 to apair of upper arms 18 which are interconnected by seat means 19. The upper arms 18 are slidably and pivotally mounted on the base bar by circular openings 20. To reduce friction during the operation of the device, the circular openings 20 can be provided with conventional bearing linings 21. Also slidably mounted on the base bar 10 and keyed thereto to prevent pivotal movement relative to the base bar 10, is a pressure assembly 22 including threaded adjusting means 23. The pressure assembly 22 consists of parallel arms 24 which are slidably mounted on and keyed to the base bar 10 by openings 25 which conform in shape to the cross-section of the base bar 10. The parallel arms 24 of the pressure assembly 22 are joined by a pivotable member 26 which is threaded to receive the adjusting means 23. The lower end 27 of the threaded adjusting means 23 bears against the upper surface of the seat means 19.

In the operation of the device of the present invention, the tool is positioned on the cylinder head of a diesel engine by threading the securing bolts 12 intothe rocker arm bolt holes corresponding to a selected cylinder. The securing bolts 12 are preferably provided with knurled heads 28 for ease of insertion. It is only necessary that the securing bolts 12 be handtightened. When the tool is in position the spring compressor assembly 13 can be moved along the base bar 10 so that the compressor unit 14 will overlie the end of a selected cam follower push rod. The threaded adjusting means 23 is then rotated clockwise to cause the end 27 to bear against the upper surface of the seat means 19. This action will in turn cause the depression of the arms 18 which are pivotally mounted on the base bar 10. The compressor unit 14 will be depressed and the terminal surface 16 of the compressor unit will contact the follower upper spring. seat which overlies the cam follower spring. Further clockwise rotation of the adjusting means 23 will cause compression of the cam follower spring. When the cam follower spring has been compressed to a point allowing access to the follower spring seat retainer, this retainer can then be removed using a screw driver, thin nose pliers or the like. Counter-clockwise rotation of the adjusting means will now cause upward movement of the compressor unit 14 under action of the cam follower spring. When the compression on the spring has been released, the tool can be slid aside along the base bar 10 and disassembly of the cam follower assembly can conveniently take place.

Replacement of the follower spring seat retainer is accomplished equally as easily using the tool of the present invention. With the cam follower assembly in place, the terminal portion 16 of the compressor unit 14 is brought into contact with the follower upper spring seat. Clockwise rotation of the adjusting means 23 will cause compression of the cam follower spring to a point permitting free access to replace the follower spring seat retainer. Counter-clockwise rotation of the adjusting means will allow the follower upper spring seat to contact the follower spring seat retainer, completing the reassembly of the cam follower assembly.

I. claim:

l. A cam follower spring compressor for use in connection with a diesel engine cylinder head having a plurality of recessed cam follower spring assemblies associated with each cylinder thereof and having threaded rocker arm bolt holes positioned in said cylinder head and spaced apart by a distance encompassing all of the cam follower springs associated with a given cylinder, said spring compressor comprising;

a base bar,

threaded securing means connected to said base bar for removably securing said base bar to said cylinder head, rocker arm spring compressing means slidably and pivotally mounted on said base bar,

rocker arm tensioning means slidably mounted on said base bar and keyed thereto to prevent pivotal motion of said rocker arm tensioning means about said base bar, and adjusting means threadably mounted on said rocker arm tensioning means and contacting said rocker arm adjusting means whereby rotational movement of the adjusting means will cause the rocker arm adjusting means to pivot downwardly or upwardly as desired.

2. A cam follower spring compressor as set forth in claim 1, wherein said rocker arm spring compressing means includes a tubular lower member adapted to directly contact a selected cam follower spring assembly.

3. A cam follower spring compressor as set forth in claim 1, wherein said threaded securing means are provided with knurled upper end portions and are adapted to threadably engage the rocker arm bolt holes in a cylinder head.

4. A cam follower spring compressor as set forth in claim 1, wherein said rocker arm spring compressing means includes a pair of spaced apart flanges slidably and pivotally mounted on said base bar and said rocker arm tensioning means is slidably mounted on said base bar intermediate said flanges.

5. A cam follower Spring compressor as set forth in claim 4, wherein said flanges are interconnected by seat means and wherein the adjusting means threadably mounted in said tensioning means is in contact with said seat means. 

1. A cam follower spring compressor for use in connection with a diesel engine cylinder head having a plurality of recessed cam follower spring assemblies associated with each cylinder thereof and having threaded rocker arm bolt holes positioned in said cylinder head and spaced apart by a distance encompassing all of the cam follower springs associated with a given cylinder, said spring compressor comprising; a base bar, threaded securing means connected to said base bar for removably securing said base bar to said cylinder head, rocker arm spring compressing means slidably and pivotally mounted on said base bar, rocker arm tensioning means slidably mounted on said base bar and keyed thereto to prevent pivotal motion of said rocker arm tensioning means about said base bar, and adjusting means threadably mounted on said rocker arm tensioning means and contacting said rocker arm adjusting means whereby rotational movement of the adjusting means will cause the rocker arm adjusting means to pivot downwardly or upwardly as desired.
 2. A cam follower spring compressor as set forth in claim 1, wherein said rocker arm spring compressing means includes a tubular lower member adapted to directly contact a selected cam follower spring assembly.
 3. A cam follower spring compressor as set forth in claim 1, wherein said threaded securing means are provided with knurled upper end portions and are adapted to threadably engage the rocker arm bolt holes in a cylinder head.
 4. A cam follower spring compressor as set forth in claim 1, wherein said rocker arm spring compressing means includes a pair of spaced apart flanges slidably and pivotally mounted on said base bar and said rocker arm tensioning means is slidably mounted on said base bar intermediate said flanges.
 5. A cam follower spring compressor as set forth in claim 4, wherein said flanges are interconnected by seat means and wherein the adjusting means threadably mounted in said tensioning means is in contact with said seat means. 